In order to realize supporting the large two-layer network of the data center, multiple overlay encapsulation technologies are proposed correspondingly, which perform the mapping study of the customer side MAC and the corresponding overlay access node identifier correspondingly through performing encapsulation and decapsulation of the original message in the edge device of the overlay network, and perform the corresponding control plane information interaction through the control plane in the overlay network, in order to carry the node identifier and interacting other information required to be carried for head encapsulation, such that it is realized that the overlay encapsulation of the original message is performed on the edge access device of the overlay network, and is then forwarded on the overlay intermediate transmission node, and reach the far end target edge device and perform the overlay decapsulation, therefore, the transmission of the original message in the large two-layer network is completed.
For example, the TRILL technology (Transparent Interconnection over Lots of Links) in the overlay encapsulation technology is a protocol used for solving the insufficient of the Spanning Tree protocol (STP) in the large-scale data center. In the two-layer network, the STP avoids the loop through blocking the redundant link, but it causes the waste (blocking) of the bandwidth of the redundant link at the same time. The TRILL solves the loop problem of the two-layer network through introducing the Intermediate System to Intermediate System (IS-IS) route protocol into the two-layer network, and realizes the multiple paths (or called the Equivalent Cost Multiple Path (ECMP)) of the two-layer network at the same time.
In the TRILL network (Campus), the device running the TRILL protocol is called as the route network bridge (RBridge), the device encapsulating the original message into the TRILL message at the entry of the network is called as the ingress route network bridge (RBridge), and the route network bridge decapsulating the TRILL data frame into the original data frame and forwarding to the end device at the exit of the TRILL network is called as the Egress route network bridge (RBridge). And the Egress RB will also study and record the information table {internal layer source MAC, Ingress_Nickname, . . . } of the data frame at the same time. The edge devices of the current overlay network all perform one-to-one mapping relationship study when studying and storing the mapping of the MAC and the overlay network device identifier.
Meanwhile, the multi-homing access is a very common network deploying scene in the data center, where the terminal accesses the network through two or more than two links. The interfaces on the devices forming a group of multi-homing access are thought to join the same link aggregation group, and these devices are thought to be the member devices in the same link aggregation group. To the TRILL network specifically, the terminal accesses the TRILL network through multiple links and through multiple ingress RBs, these uplinks and the ingress RBridges make up one multi-homing group, and the RBridge device runs the link aggregation protocol (such as IEEE 802.1AX-REV). Because the message sent by the terminal may be encapsulated by different RBridges which belong to the multi-homing group, in this way, when the egress RBridge of the far end performs the MAC study, the frequently stir (called the flip-flop) of the Ingress-Nickname of the MAC table entry will occur since the same one MAC can only study the mapping of only one overlay network device identifier, which causes the instability of the MAC address table, and even will cause the disordered sequence of the returning flow and packet loss, resulting in the breakoff of the conversation.
As shown in FIG. 1, the customer side device 1 is connected to the RB1 and the RB2 at the same time, so the terminal accesses the links of the RB1 and the RB2 respectively and then forms one multi-homing group. When the customer side device 1 communicates with the customer side device 3, the two links of the RB1 and the RB2 connecting the customer side device 1 form the multi-homing binding relationship; the MAC1 on the customer side device 1 forms the TRILL encapsulation to reach the RB5 through the RB1 first, and the RB5 studies the mapping relationship between the nickname of the RB1 and the MAC1; when the flow of the MAC1 coming from the RB2 reaches the RB5, the RB5 will study the mapping relationship between the nickname of the RB2 and the MAC1, and covers the mapping relationship between the nickname of the RB1 and the MAC1. When there are MAC1 flow sent to the RB5 ceaselessly from the RB1 and the RB2 at the same time, the MAC1 related entries on the RB5 will be incessantly refreshed and covered. To other overlay networks, such as the SPB network, etc., when the terminal accesses multiple network bridges of the SPB network through the multi-homing access mode, the problem of the above-mentioned flip-flop of MAC table entry also exists.